Turbojet engine having tail pipe ejector to induce flow of cooling air



May 26, 1953 D. WILLGOOS TURBOJET ENGINE HAVING TAIL PIPE EJECTOR TOINDUCE FLOW OF' COOLING AIR Original Filed June 2]., 1949 mm. w)

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Q NP) u m N OOM ONO I Y' hu Ohm. www QON WON .NA N WAM. ONO N mmm S QON@NN NNO QN @9M 5% ONM OWN @QN QN ON, OR, ODM NEN l Y nu@ @NN OOOOOOOOlnmu WNY OMM OWN. On mw l o QON NNO r o @NM QON WORM@ S OOO 1| hm. i@OQO 1G MOO Rw www @QE mw\ www@ u awm Patented May 26, 1953 OFFICEA'IU'RBOJET- ENGINE HAVING TAIL PIPE EJEC'roR To INDUCE FLOW oF oooL-ING AIR Andrew V. D. Willgoos, deceased, late of West Hartford, Conn.,by Hartford National Bank and Trust Company 'of Hartford, Conn., execu-Ator, assignor to United Aircraft Corporation,

East Hartford,

Ware

Conn., a corporation of Delaoriginal application June 21, 1949, serialNo. 100,418. Divided and this application August 4, 1951, serai N9.240,346

reclaim-s. f (o1. fao-35.6)

This invention relates to gasturbine power plants.

This application is a division of copending application Serial No.100,418 filed June l21, 1949.

One feature of the invention is the arrangement for cooling certain ofthe structural elements to prevent overheating and to maintain thestructural elements at the lnecessary low temperature to maintain therequired strength. Another feature is the arrangement of the tail pipeto provide an ejector action to encourage a flow of cooling air throughthe power plant.

Other objects and advantages will be apparent from the specification andclaims and from the accompanying drawing which illustrates an embodimentof the invention.

Fig. 1 is a sectional view through the turbine and thrust nozzle.

Fig. 2 is a sectional view through the seal ring which extends aroundthe splines on the turbine rotor.

The gas turbine power plant includes a com` pressor (not shown) which isdriven by the turbine and discharges gas into one or a series ofcombustion chambers I4 enclosed within a burner case I6. From thecombustion chambers the air from the compressor with which fuel has beenmixed and burned passes through the turbine section I8 of the powerplant and is discharged through the thrust nozzleV 20.

The turbine which drives the compressor includes a turbine casing 246having spaced rows of vanes 248. Within the casing is the rotor havingrows of blades 250 on discs 252 alternating with the rows of vanes. Thecasing is supported within the turbine housing or frame section 208 by aplurality of radially extending pins 254 positioned in radial openings256 in the housing and fitting within bosses 258 on the turbine cas'-ing. The diameter of the casing at the point where the latter issupported is smaller than the corresponding diameter of the outerhousing, vto permit radial expansion of the turbine casing. In thearrangement shown, the casing 'is built up of a turbine inlet nozzlering 260 and additional nozzle rings 262 and 264, each of which carriesone row of the "turbine vanes. These rings are bolted together as by thebolts 266 and are preferably split as shown with the halves fastenedtogether as by bolts 268. The housing 208 may have normally cappedaccess openings 269 therein which have no function in the operation ofthe device.

Each of the vanes 248 is securely attached at its outer end as by beingweldedto a ring. V210 which is in turn welded to the correspondingcasing ring. At the inner end, each turbine vane has a projecting lug212 which fits in a groove 214 provided in a sealing element 216. Thelatter has inwardly extending flanges 218 which cooperate with sealingrings 280 mounted on the rotor between adjacent discs.

`The turbine rotor may have the blades attached to the discs by anysuitable means, the blades, in the arrangement shown, being Welded tothe discs. Each disc has face splines 282 on opposite ends thereofwhich, when the discs are assembled, intermesh and align the discs withone another. At opposite ends of the turbine discs are end-bells 284 and286. Within the end-bell 284 is a supporting ring 288 which receives andsupports the head of a through bolt 290 which extends through the discsand receives a nut 292 which engages with the opposite endbell 286 tohold the assembly of discs together. The nut 292 may be locked in placeby a splined sleeve 294. It will be noted that the discs are out ofcontact with the through bolts with the exception of a series of smallpiloting lugs 296 on the bolt which engage with the first stage disc.

Cooling air from the compressor flows through openings 298 in the ring288 to the internal part of the turbine rotor. The face splines are soconstructed that air passages exist between the bases of ythe groovesand the cooperating teeth sov that air flows past the splines andthrough small openings 300, Fig. 2, provided in the sealing sleeve 280so that air escaping through these passages flows over the surfaces ofthe rotor discs for cooling them.

The turbine is supported'at the discharge end by a bearing support 302having projecting legs 304 guided within the turbine housing 208 byradial pins 306. Within the bearing mounting 302 is bearing 308 engagingwith a ring 3I0 on the outer surface of the end-bell. Lubricant issupplied to Ithe bearing through a pipe 312 through one of the legs 304and the bearing is 4enclosed within a chamber 3I4 by a seal 3I6 at oneside of the bearing and a cover plate 3|8 supported on the bearingmounting and enclosing the end of the rotor. Oil collecting within thechamber 314 is scavenged through the same supporting leg 304 thatcarries the pressurized oil and is pumped out through a connecting duct320. For the purpose of cooling the bearing, the remaining legs areprovidedV with ram air inlets 322 which direct air into the housingaround thebearing for discharge through a cen- 3 trifugal fan 325 on theend-bell 286 and thence into a conical shield' 326 which surrounds theturbine bearing and forms the inner wall of the gas path for the exhaustgas from the turbine. A stiiening ring 321 surrounding the fan 325 has anumber of large diameter; openings, 323':

therein. The downstream end of this cone is.

open as at 328 for the discharge of the cooling air from the bearing.The bearingspace 3M` and also between the outermost shield. 332 and.

from the spaces between theshield. A shell 342 I secured to the turbinecasing 234 forms the outer wall of the passage 338 for-the exhaust gasfrom the turbine and this shell terminates at thesame point that theshield` 33 6 terminates. The duct 3,38 terminates in a thrustv nozzle343at a pointl downstream from the lower end ofv shell 342. The Wall 340`may have normally capped access openings 34| which have no function.inthe operation of the power plant.

At the upstream end, the shields 334 and 33,5` have mounted thereonshield extensions 344 extending inwardly to surround the turbine inletThenozzle ring and the inlet manifold 2:20. latter, as will be apparent,forms an annular chamber connecting with nozzlering 260 and,

at its upstream end, has spaced inlets connecting..`

with the ends of the combustion chambers; The

ram air pressure existing around the burnerse-is' sealed from the rotorsby a flexible seal 346;

It is to beunderstood that the inventionisnot limited to the specicembodiment herein illustrated and described, but may be used in otherways without departure from its spirit as defined by the followingclaims.

What is claimed is:

1. In a gas turbine power plant, a turbine including a rotor and asurrounding casing, a housing surrounding. the casing, supporting meansextending between the turbine casing and' the housing for supporting thecasing withiny the housing, a thrust nozzle through which gas fromtheturbine is discharged, andY an exhaust ductY connecting the turbineto the nozzle, in combina'-y tion with at least one radiation shieldlocated between and spaced from the turbine casing and housing andsurrounding the casing, the downstream end of the shield beingconcentric to and closely spaced from the exhaust duct to dene anejector located within the duct upstream of' the thrust nozzle andcommunicating with' the space between the shield and housing for main-ytaining a flow of cooling air therethrough.

2. In a gas turbine powerplant, aturbine in cluding a rotor and asurrounding-casing, a hous-r` ing surrounding the-casing, supporting#means extending `between the turbine casing and the housing. 'forsupporting the, casingv within the housing, a thrustv nozzle throughwhich gas from the turbine is discharged, and an exhaust duct connectingthe turbine to the nozzle, in combinationvwith'lat leastzone radiationshield located betweengand` spaced from the turbine casing and housingand-surrounding the casing, the downstreamY end of the shield beingconcentric to and closely spaced from the exhaust duct to dene an,ejector located within the duct upstream of` the thrust. nozzle andcommunicating with the'space: between the shield. and housing formaintaining a ow ,of cooling air therethrough, the forward end ofv thespace between the casing and housing communicating with a source of airunder pressure.

3. In a gas turbine power plant, a turbine includinga rotor and asurrounding casing, a housing surrounding the casing, supporting meansbetween the housing and casing for supporting the turbine casing withinthe housing, other sup-- porting means betweenthe housingv and rotor forsupportingthe rotor within the housing, a thrust nozzle in axialalignment with the turbine through which gas from the turbine isdischarged, and an exhaust duct from the turbine to the nozzle incombination with a shieldv surroundingy the turbine casing and locatedbetween and. spaced ,from the.l housing andv casing, the downstream,endofk the shield being concentric to and closely spaced fromthe wallsof the duct upstream ofthe .nozzley and cooperating with the duct. toforml an ejector for causing a ow ofair over the shield..

4. In a gas turbine power plant, a turbine including a rotor and avsurrounding casing, a housing surrounding and supporting, the turbinecasing and a thrustI nozzle in, axial alignment with the. turbine,through which gas from the` turbine is discharged, said nozzle havingan outer wall` forming.` a continuation. of the turbine housingincombination. with ashield surrounding the turbine casing. and4 locatedbetween the housing and casingthey downstream end of the shieldbeingwithin and. concentric to. and closely spaced. fromtheouter wall ofthe. nozzle to form an ejector for` ,causing` a flowv of air over theshield, the forward endlof the space between the.

shield and housing communicating with a source of cooling air.,

5'.v In a gas turbine power plant, a turbine including a rotor andasurrounding casing, a housing surrounding and supporting the turbinecasing and a thrust. nozzle in axial. alignment with the turbine,throughwhichgas fromthe turbine is discharged,vsaid nozzle having anouter wall forming a continuation of' the, turbine housing, incombination with, a.. shield? surrounding the turbine vcasing andlocatedl between ,the` housing and` casing,v the, downstream endi ofthev shield being within and concentric to and closely spaced from; theouter wall' ofthe nozzle tov form, an,

tweemthe casingt andI housing, andinaspaced re lation thereto, andextending to a point downstream of the turbine, the downstream end ofthe shield being concentric to and closely adjacent to the outer wall toform an ejector nozzle.

7. In a gas turbine power plant, a turbine including a rotor and asurrounding casing, a housing surrounding and supporting the turbinecasing and a thrust nozzle in axial alignment with the turbine throughwhich gas from the turbine is discharged, said nozzle having an outerwall forming a continuation of the turbine housing, in combination witha shield located between the casing and housing, and in spaced relationthereto, and extending to a point downstream of the turbine, thedownstream end of the shield being concentric to and closely adjacent tothe outer wall to form an ejector nozzle, the upstream end of the spacebetween the shield and housing communicating with a source of coolingair.

8. In a gas turbine power plant, a turbine including a rotor and asurrounding casing, a housing surrounding and supporting the turbinecasing and a thrust nozzle in axial alignment with the turbine throughwhich gas from the turbine is discharged, said nozzle having an outerwall forming a continuation of the turbine housing, in combination witha shield forming a downstream extension of the turbine casing andarranged concentrically within and spaced from the outer wall, thedownstream end of said shield being concentric to and closely adjacentto said outer wall to form an ejector nozzle.

9. In a gas turbine power plant, a turbine including a rotor and asurrounding casing, a housing surrounding and supporting the turbinecasing and a thrust nozzle in axial alignment with the turbine throughwhich gas from the turbine is discharged, said nozzle having an outerwall forming a continuation of the turbine housing, in

combination with a shield forming a downstream extension of the turbinecasing and arranged concentrically within and spaced from the outerwall, the downstream end of said shield being concentric to and closelyadjacent to said outer wall to form an ejector nozzle, and avforwardlydirected air inlet connected to the upstream end of the space betweenthe casing and housing.

10. In a gas turbine power plant, a turbine including a rotor and asurrounding casing, a housing surrounding and supporting the turbinecasing and a thrust nozzle in axial alignment with the turbine throughwhich gas from the turbine is discharged, said nozzle having an outerwall forming a continuation of the turbine housing, in combination witha shield forming a downstream extension of the turbine casing andarranged concentrically within the outer wall, the downstream end ofsaid shield being closely adjacent to said outer wall to form an ejectornozzle, and annular radiation shields between the casing and housingaround and between which a flow of air is induced by said ejector.

HARTFORD NATIONAL BANK AND TRUST COMPANY, By GREELY STURDIVANT,

Trust O17icer, Eecutor of the estate of Andrew V. D. Willgoos, deceased.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,579,114 Halford et al. Dec. 18, 1951 2,589,945 Leduc Mar.18, 1952 FOREIGN PATENTS Number Country Date 196,452 Great Britain Apr.26, 1923

